Films having desirable mechanical properties and articles made therefrom

ABSTRACT

Disclosed herein is a film comprising a layer that comprises a polyethylene composition comprising the reaction product of ethylene and optionally one or more alpha-olefin comonomers, wherein said polyethylene composition is characterized by the following properties: a melt index, I2, measured according to ASTM D1238 (2.16 kg, 190 C), of from 0.5 to 10 g/10 min; a density (measured according to ASTM D792) of less than 0.935 g/cm3; a melt flow ratio, I10/I2, wherein I10 is measured according to ASTM D1238 (10 kg, 190 C) of from 6.0 to 7.5; a molecular weight distribution (Mw/Mn) of from 2.8 to 3.9; and a vinyl unsaturation of greater than 0.12 vinyls per one thousand carbon atoms, and a low density polyethylene.

FIELD

Embodiments of the present disclosure generally relate to films havingdesirable mechanical properties and to articles made from such films.Examples of such articles include flexible packages.

BACKGROUND

Polyethylene films are widely used in a variety of products including,for example, flexible packaging applications. Flexible package films maytypically be made from blends of linear low density polyethylene (LLDPE)and low density polyethylene (LDPE). A number of mechanical propertiesare important for films to be used in flexible packaging applicationsincluding, for example, dart impact resistance, puncture, and tear.Existing films for flexible packaging can sometimes provide somedesirable mechanical properties, but at the expense of one or more otherproperties.

Accordingly, films having a combination of high puncture and dart impactresistance without reducing tear resistance are desired.

SUMMARY

Disclosed in embodiments herein are films which provide one or moredesirable mechanical properties or a combination of properties. In someembodiments, films of the present invention provide a desirablecombination of puncture, dart impact resistance, and tear resistance.Such films, in some embodiments, can be used in articles such asflexible packages.

In one aspect, films of the present invention comprise a layercomprising (a) 50% or more by weight of a polyethylene compositioncomprising the reaction product of ethylene and optionally one or morealpha-olefin comonomers, wherein said polyethylene composition ischaracterized by the following properties: a melt index, I₂, measuredaccording to ASTM D1238 (2.16 kg, 190° C.), of from 0.5 to 10 g/10 min;a density (measured according to ASTM D792) of less than 0.935 g/cm³; amelt flow ratio, I₁₀/I₂, wherein I₁₀ is measured according to ASTM D1238(10 kg, 190° C.) of from 6.0 to 7.5; a molecular weight distribution(M_(w)/M_(n)) of from 2.8 to 3.9; and a vinyl unsaturation of greaterthan 0.12 vinyls per one thousand carbon atoms; and (b) 50% or less byweight of a low density polyethylene.

Also disclosed herein are articles comprising a film according to any ofthe embodiments disclosed herein. For example, in one aspect, films usedin such articles comprise a layer comprising (a) 50% or more by weightof a polyethylene composition comprising the reaction product ofethylene and optionally one or more alpha-olefin comonomers, whereinsaid polyethylene composition is characterized by the followingproperties: a melt index, I₂, measured according to ASTM D1238 (2.16 kg,190° C.), of from 0.5 to 10 g/10 min; a density (measured according toASTM D792) of less than 0.935 g/cm³; a melt flow ratio, I₁₀/I₂, whereinI₁₀ is measured according to ASTM D1238 (10 kg, 190° C.) of from 6.0 to7.5; a molecular weight distribution (M_(w)/M_(n)) of from 2.8 to 3.9;and a vinyl unsaturation of greater than 0.12 vinyls per one thousandcarbon atoms; and (b) 50% or less by weight of a low densitypolyethylene.

These and other embodiments are described in more detail in the DetailedDescription.

DETAILED DESCRIPTION

Unless stated to the contrary, implicit from the context, or customaryin the art, all parts and percentages are based on weight, alltemperatures are in ° C., and all test methods are current as of thefiling date of this disclosure.

The term “composition,” as used herein, refers to a mixture of materialswhich comprises the composition, as well as reaction products anddecomposition products formed from the materials of the composition.

Reference will now be made in detail to embodiments of films andarticles, examples of which are further described below. In someembodiments, the films may have a desirable combination of puncture,dart impact resistance, and tear resistance and may be used in flexiblepackages. It is noted, however, that this is merely an illustrativeimplementation of the embodiments disclosed herein. The embodiments areapplicable to other technologies that are susceptible to similarproblems as those discussed above. The film may be a monolayer film or amultilayer film. As used herein, “multilayer film” refers to a filmhaving two or more layers that are at least partially contiguous andpreferably, but optionally, coextensive.

In some embodiments, a film of the present invention comprises a layer,the layer comprising (a) 50% or more by weight of a polyethylenecomposition comprising the reaction product of ethylene and optionallyone or more alpha-olefin comonomers, wherein said polyethylenecomposition is characterized by the following properties: a melt index,I₂, measured according to ASTM D1238 (2.16 kg, 190° C.), of from 0.5 to10 g/10 min; a density (measured according to ASTM D792) of less than0.935 g/cm³; a melt flow ratio, I₁₀/I₂, wherein I₁₀ is measuredaccording to ASTM D1238 (10 kg, 190° C.) of from 6.0 to 7.5; a molecularweight distribution (M_(w)/M_(n)) of from 2.8 to 3.9; and a vinylunsaturation of greater than 0.12 vinyls per one thousand carbon atoms;and (b) 50% or less by weight of a low density polyethylene.

In some embodiments, the polyethylene composition is formed in thepresence of a catalyst composition comprising a multi-metallicprocatalyst via solution polymerization in at least one reactor. In somefurther embodiments, the solution polymerization occurs in a singlereactor. The polyethylene composition, in some embodiments, has a metalcatalyst residual of greater than or equal to 1 parts by combined weightof at least three metal residues per one million parts of polyethylenepolymer, wherein the at least three metal residues are selected from thegroup consisting of titanium, zirconium, hafnium, vanadium, niobium,tantalum, chromium, molybdenum, tungsten, and combinations thereof, andwherein each of the at least three metal residues is present at greaterthan or equal to 0.2 ppm. In some embodiments, the polyethylenecomposition has an Al:Ti ratio of from 6 to 15.

In some embodiments, the film comprises 5 to 30% by weight of the lowdensity polyethylene. The low density polyethylene, in some embodiments,has a melt index, I₂, of 0.1 to 5 g/10 minutes.

In embodiments herein, the film layer comprises 50% or more by weight ofa polyethylene composition. The film layer comprises from 50 to 99percent, 55 to 99 percent, 60 to 99 percent, 65 to 99 percent, 70 to 99percent, 75 to 99 percent, 80 to 99 percent, 85 to 99 percent, 90 to 99percent, or 95 to 99 percent, by total weight of polymers present in thefilm layer, of the polyethylene composition.

In some embodiments, films of the present invention comprise a layercomprising (a) 70% or more by weight of a polyethylene compositioncomprising the reaction product of ethylene and optionally one or morealpha-olefin comonomers, wherein said polyethylene composition ischaracterized by the following properties: a melt index, I₂, measuredaccording to ASTM D1238 (2.16 kg, 190° C.), of from 0.5 to 2 g/10 min; adensity (measured according to ASTM D792) of less than 0.935 g/cm³; amelt flow ratio, I₁₀/I₂, wherein I₁₀ is measured according to ASTM D1238(10 kg, 190° C.) of from 6.5 to 7.5; a molecular weight distribution(M_(w)/M_(n)) of from 2.8 to 3.9; and a vinyl unsaturation of greaterthan 0.12 vinyls per one thousand carbon atoms; and (b) 30% or less byweight of a low density polyethylene.

The polyethylene composition comprises the reaction product of ethyleneand optionally one or more alpha-olefin comonomers. The polyethylenecomposition comprises greater than 50 wt. % of the units derived fromethylene and less than 30 wt. % of the units derived from one or morealpha-olefin comonomers. In some embodiments, the polyethylenecomposition comprises (a) greater than or equal to 55%, for example,greater than or equal to 60%, greater than or equal to 65%, greater thanor equal to 70%, greater than or equal to 75%, greater than or equal to80%, greater than or equal to 85%, greater than or equal to 90%, greaterthan or equal to 92%, greater than or equal to 95%, greater than orequal to 97%, greater than or equal to 98%, greater than or equal to99%, greater than or equal to 99.5%, from greater than 50% to 99%, fromgreater than 50% to 97%, from greater than 50% to 94%, from greater than50% to 90%, from 70% to 99.5%, from 70% to 99%, from 70% to 97% from 70%to 94%, from 80% to 99.5%, from 80% to 99%, from 80% to 97%, from 80% to94%, from 80% to 90%, from 85% to 99.5%, from 85% to 99%, from 85% to97%, from 88% to 99.9%, 88% to 99.7%, from 88% to 99.5%, from 88% to99%, from 88% to 98%, from 88% to 97%, from 88% to 95%, from 88% to 94%,from 90% to 99.9%, from 90% to 99.5% from 90% to 99%, from 90% to 97%,from 90% to 95%, from 93% to 99.9%, from 93% to 99.5% from 93% to 99%,or from 93% to 97%, by weight, of the units derived from ethylene; and(b) optionally, less than 30 percent, for example, less than 25 percent,or less than 20 percent, less than 18%, less than 15%, less than 12%,less than 10%, less than 8%, less than 5%, less than 4%, less than 3%,less than 2%, less than 1%, from 0.1 to 20%, from 0.1 to 15%, 0.1 to12%, 0.1 to 10%, 0.1 to 8%, 0.1 to 5%, 0.1 to 3%, 0.1 to 2%, 0.5 to 12%,0.5 to 10%, 0.5 to 8%, 0.5 to 5%, 0.5 to 3%, 0.5 to 2.5%, 1 to 10%, 1 to8%, 1 to 5%, 1 to 3%, 2 to 10%, 2 to 8%, 2 to 5%, 3.5 to 12%, 3.5 to10%, 3.5 to 8%, 3.5% to 7%, or 4 to 12%, 4 to 10%, 4 to 8%, or 4 to 7%,by weight, of units derived from one or more α-olefin comonomers. Thecomonomer content may be measured using any suitable technique, such astechniques based on nuclear magnetic resonance (“NMR”) spectroscopy,and, for example, by 13C NMR analysis as described in U.S. Pat. No.7,498,282, which is incorporated herein by reference.

Suitable comonomers may include alpha-olefin comonomers, typicallyhaving no more than 20 carbon atoms. The one or more alpha-olefins maybe selected from the group consisting of C₃-C₂₀ acetylenicallyunsaturated monomers and C₄-C₁₈ diolefins. Those skilled in the art willunderstand that the selected monomers are desirably those that do notdestroy conventional Ziegler-Natta catalysts. For example, thealpha-olefin comonomers may have 3 to 10 carbon atoms, or 3 to 8 carbonatoms. Exemplary alpha-olefin comonomers include, but are not limitedto, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene,1-nonene, 1-decene, and 4-methyl-1-pentene. The one or more alpha-olefincomonomers may, for example, be selected from the group consisting ofpropylene, 1-butene, 1-hexene, and 1-octene; or in the alternative, fromthe group consisting of 1-butene, 1-hexene and 1-octene. In someembodiments, the polyethylene composition comprises greater than 0 wt. %and less than 30 wt. % of units derived from one or more of octene,hexene, or butene comonomers.

In some embodiments, the polyethylene composition is formed in thepresence of a catalyst composition comprising a multi-metallicprocatalyst via solution polymerization in at least one reactor. Inother embodiments, the polyethylene composition is formed in thepresence of a catalyst composition comprising a multi-metallicprocatalyst comprising of three or more transition metals via solutionpolymerization in at least one reactor. In some embodiments, thesolution polymerization occurs in a single reactor. The multi-metallicprocatalyst used in producing the reaction product is at leasttrimetallic, but may also include more than three transition metals, andthus may in one embodiment be defined more comprehensively asmulti-metallic. These three, or more, transition metals are selectedprior to production of the catalyst. In a particular embodiment, themulti-metal catalyst comprises titanium as one element.

The catalyst compositions may be prepared beginning first withpreparation of a conditioned magnesium halide-based support. Preparationof a conditioned magnesium halide-based support begins with selecting anorganomagnesium compound or a complex including an organomagnesiumcompound. Such compound or complex is desirably soluble in an inerthydrocarbon diluent. The concentrations of components are preferablysuch that when the active halide, such as a metallic or non-metallichalide, and the magnesium complex are combined, the resultant slurry isfrom about 0.005 to about 0.25 molar (moles/liter) with respect tomagnesium. Examples of suitable inert organic diluents include liquefiedethane, propane, isobutane, n-butane, n-hexane, the various isomerichexanes, isooctane, paraffinic mixtures of alkanes having from 5 to 10carbon atoms, cyclohexane, methylcyclopentane, dimethylcyclohexane,dodecane, industrial solvents composed of saturated or aromatichydrocarbons such as kerosene, naphthas, and combinations thereof,especially when freed of any olefin compounds and other impurities, andespecially those having boiling points in the range from about −50° C.to about 200° C. Also included as suitable inert diluents areethylbenzene, cumene, decalin and combinations thereof.

Suitable organomagnesium compounds and complexes may include, forexample, magnesium C₂-C₈ alkyls and aryls, magnesium alkoxides andaryloxides, carboxylated magnesium alkoxides, and carboxylated magnesiumaryloxides. Preferred sources of magnesium moieties may include themagnesium C₂-C₈ alkyls and C₁-C₄ alkoxides. Such organomagnesiumcompound or complex may be reacted with a metallic or non-metallichalide source, such as a chloride, bromide, iodide, or fluoride, inorder to make a magnesium halide compound under suitable conditions.Such conditions may include a temperature ranging from −25° C. to 100°C., alternatively, 0° C. to 50° C.; a time ranging from 1 to 12 hours,alternatively, from 4 to 6 hours; or both. The result is a magnesiumhalide based support.

The magnesium halide support is then reacted with a selectedconditioning compound containing an element selected from the groupconsisting of boron, aluminum, gallium, indium and tellurium, underconditions suitable to form a conditioned magnesium halide support. Thiscompound and the magnesium halide support are then brought into contactunder conditions sufficient to result in a conditioned magnesium halidesupport. Such conditions may include a temperature ranging from 0° C. to50° C., or alternatively, from 25° C. to 35° C.; a time ranging from 4to 24 hours, or alternatively, from 6 to 12 hours; or both. Theconditioning compound has a molar ratio constitution that is specificand which is believed to be an important feature in ensuring thedesirable catalyst performance. Specifically, the procatalyst desirablyexhibits a molar ratio of the magnesium to the conditioning compoundthat ranges from 3:1 to 6:1. Without wishing to be bound by any theoryof mechanism, it is suggested that this aging serves to facilitate orenhance adsorption of additional metals onto the support.

Once the conditioned support is prepared and suitably aged, it isbrought into contact with a titanium compound which may be addedindividually or as a mixture with the “second metal”. In certainpreferred embodiments titanium halides or alkoxides, or combinationsthereof, may be selected. Conditions may include a temperature withinthe range from 0° C. to 50° C., alternatively from 25° C. to 35° C.; atime from 3 hours to 24 hours, alternatively from 6 hours to 12 hours;or both. The result of this step is adsorption of at least a portion ofthe titanium compound onto the conditioned magnesium halide support.

Finally, one or two additional metals, referred to herein as “the secondmetal” and “the third metal” for convenience, will also be adsorbed ontothe magnesium-based support, The “second metal” and the “third metal”are independently selected from zirconium (Zr), hafnium (Hf), vanadium(V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), andtungsten (W). These metals may be incorporated in any of a variety ofways known to those skilled in the art, but generally contact betweenthe conditioned magnesium based halide support including titanium andthe selected second and third metals, in, e.g., liquid phase such as anappropriate hydrocarbon solvent, will be suitable to ensure depositionof the additional metals to form what may now be referred to as the“procatalyst,” which is a multi-metallic procatalyst.

The multi-metallic procatalyst has a molar ratio constitution that isspecific and which is believed to be an important feature in ensuringthe desirable polymer properties that may be attributed to the catalystmade from the procatalyst. Specifically, the procatalyst desirablyexhibits a molar ratio of the magnesium to a combination of the titaniumand the second and third metals that ranges from 30:1 to 5:1; underconditions sufficient to form a multi-metallic procatalyst. Thus, theoverall molar ratio of magnesium to titanium ranges from 8:1 to 80:1. Insome embodiments, the Al:Ti ratio is from 6 to 15, 7 to 14, 7 to 13, 8to 13, 9 to 13, or 9 to 12.

Once the procatalyst has been formed, it may be used to form a finalcatalyst by combining it with a cocatalyst consisting of at least oneorganometallic compound such as an alkyl or haloalkyl of aluminum, analkylaluminum halide, a Grignard reagent, an alkali metal aluminumhydride, an alkali metal borohydride, an alkali metal hydride, analkaline earth metal hydride, or the like. The formation of the finalcatalyst from the reaction of the procatalyst and the organometalliccocatalyst may be carried out in situ, or just prior to entering thepolymerization reactor. Thus, the combination of the cocatalyst and theprocatalyst may occur under a wide variety of conditions. Suchconditions may include, for example, contacting them under an inertatmosphere such as nitrogen, argon or other inert gas at temperatures inthe range from 0° C. to 250° C., preferably from 15° C. to 200° C. Inthe preparation of the catalytic reaction product, it is not necessaryto separate hydrocarbon soluble components from hydrocarbon insolublecomponents. Time for contact between the procatalyst and cocatalyst maydesirably range, for example, from 0 to 240 seconds, preferably from 5to 120 seconds. Various combinations of these conditions may beemployed.

In embodiments described herein, the polyethylene composition may have ametal catalyst residual of greater than or equal to 1 parts by combinedweight of at least three metal residues per one million parts ofpolyethylene polymer, wherein the at least three metal residues areselected from the group consisting of titanium, zirconium, hafnium,vanadium, niobium, tantalum, chromium, molybdenum, tungsten, andcombinations thereof, and wherein each of the at least three metalresidues is present at greater than or equal to 0.2 ppm, for example, inthe range of from 0.2 to 5 ppm. All individual values and subranges fromgreater than or equal to 0.2 ppm are included herein and disclosedherein; for example, the polyethylene composition may further comprisegreater than or equal to 2 parts by combined weight of at least threemetal residues remaining from the multi-metallic polymerization catalystper one million parts of the polyethylene composition.

In embodiments described herein, the polyethylene composition may have ametal catalyst residual of greater than or equal to 1 parts by combinedweight of at least three metal residues per one million parts ofpolyethylene polymer, wherein the at least three metal residues areselected from the group consisting of titanium, zirconium, hafnium,vanadium, niobium, tantalum, chromium, molybdenum, tungsten, andcombinations thereof, and wherein each of the at least three metalresidues is present at greater than or equal to 0.4 ppm, for example, inthe range of from 0.4 to 5 ppm. All individual values and subranges fromgreater than or equal to 0.4 ppm are included herein and disclosedherein; for example, the polyethylene composition may further comprisegreater than or equal to 2 parts by combined weight of at least threemetal residues remaining from the multi-metallic polymerization catalystper one million parts of the polyethylene composition.

In some embodiments, the polyethylene composition comprises at least0.75 ppm of V (Vanadium). All individual values and subranges from atleast 0.75 ppm of V are included and disclosed herein; for example thelower limit of the V in the polyethylene composition may be 0.75, 1,1.1, 1.2, 1.3 or 1.4 ppm to an upper limit of the V in the polyethylenecomposition may be 5, 4, 3, 2, 1.9, 1.8, 1.7, 1.6, 1.5, or 1 ppm. Thevanadium catalyst metal residual concentration for the polyethylenecomposition can be measured using the Neutron Activation Method forMetals described below.

In some embodiments, the polyethylene composition comprises at least 0.3ppm of Zr (Zirconium). All individual values and subranges of at least0.3 ppm of Zr are included and disclosed herein; for example the lowerlimit of the Zr in the polyethylene composition may be 0.3, 0.4, 0.5,0.6 or 0.7 ppm. In yet another embodiment, the upper limit of the Zr inthe polyethylene composition may be 5, 4, 3, 2, 1, 0.9, 0.8 or 0.7 ppm.The zirconium catalyst metal residual concentration for the polyethylenecomposition can be measured using the Neutron Activation Method forMetals described below.

In embodiments described herein, the polyethylene composition has adensity of less than 0.935 g/cm³. In some embodiments, the polyethylenecomposition has a density of 0.900 g/cm³ to less than 0.935 g/cm³. Allindividual values and subranges of 0.900 g/cm³ up to 0.935 g/cm³ areincluded and disclosed herein. For example, in some embodiments, thepolyethylene composition may have a density ranging from a lower limitof 0.900, 0.903, 0.905, 0.910, 0.912, 0.915, 0.917, 0.918, 0.920, 0.922,0.925, 0.926, 0.927, or 0.930 g/cm³ to an upper limit of 0.920, 0.922,0.925, 0.928, 0.930, 0.932, 0.934, or 0.935 g/cm³. In other embodiments,the polyethylene composition may have a density of 0.910 to 0.930 g/cm³,0.915 to 0.928 g/cm³, 0.910 to 0.924 g/cm³, 0.915 to 0.925 g/cm³, 0.912to 0.928 g/cm³, or 0.916 to 0.932 g/cm³. Density may be measured inaccordance with ASTM D792.

In embodiments described herein, the polyethylene composition has a meltindex, I₂, of 0.5 g/10 min to 10 g/10 min. All individual values andsubranges of at least 0.5 g/10 min to 10 g/10 min are included anddisclosed herein. For example, in some embodiments, the polyethylenecomposition may have melt index, I₂, ranging from a lower limit of 0.5,0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.4, 3.5, 4.0, or 4.5 to anupper limit of 10, 9, 8, 7, 6, 5, 4, 3, or 2 g/10 min. In otherembodiments, the polyethylene composition may have a melt index, I₂, of0.5 g/10 min to 7 g/10 min, 0.5 g/10 min to 5 g/10 min, or 0.5 g/10 minto 2.5 g/10 min. In some embodiments, the polyethylene composition mayhave a melt index, I₂, of 0.5 g/10 min to 2.0 g/10 min, 0.5 g/10 min to1.8 g/10 min, 0.5 g/10 min to 1.5 g/10 min, or 0.5 g/10 min to 1.3 g/10min. In further embodiments, the polyethylene composition may have amelt index, I₂, of 1.0 g/10 min to 10 g/10 min, 1.0 g/10 min to 5 g/10min, or 1.0 g/10 min to 4.5 g/10 min. Melt index, I₂, may be measured inaccordance with ASTM D1238 (190° C. and 2.16 kg).

In embodiments described herein, the polyethylene composition has a meltflow ratio, I₁₀/I₂, of from 6.0 to 7.5. All individual values andsubranges of from 6.0 to 7.5 are included and disclosed herein. Forexample, in some embodiments, the polyethylene composition may have amelt flow ratio, I₁₀/I₂, ranging from a lower limit of 6.0, 6.1, 6.2,6.3, 6.4, 6.5, 6.6, or 6.7 to an upper limit of 7.5, 7.4, or 7.35. Inother embodiments, the polyethylene composition may have a melt flowratio, I₁₀/I₂, of from 6.1 to 7.5, 6.2 to 7.5, 6.3 to 7.5, 6.4 to 7.5,or 6.5 to 7.5. Melt index, I₁₀, may be measured in accordance with ASTMD1238 (190° C. and 10.0 kg).

In embodiments described herein, the polyethylene composition has amolecular weight distribution (M_(w)/M_(n)) of from 2.8 to 3.9. Allindividual values and subranges of from 2.8 to 3.9 are included anddisclosed herein. For example, the polyethylene composition may have anM_(w)/M_(n) ratio from a lower limit of 2.8, 2.9, 3.0, 3.1, 3.2, or 3.3to an upper limit of 3.9, 3.8, 3.7, 3.6, 3.5, 3.4, 3.3, 3.2, 3.1, 3.0,or 2.9. In some embodiments, the polyethylene composition may have anM_(w)/M_(n) ratio of from 2.8 to 3.9, 2.9 to 3.9, 3.0 to 3.9, 3.1 to3.9, 3.2 to 3.9, 3.3 to 3.9, or 3.5 to 3.8. Molecular weightdistribution can be described as the ratio of weight average molecularweight (M_(w)) to number average molecular weight (M_(n)) (i.e.,M_(w)/M_(n)), and can be measured by gel permeation chromatographytechniques.

In embodiments described herein, the polyethylene composition has numberaverage molecular weight (M_(n)) from 25,000 to 50,000 g/mol, from30,000 to 40,000 g/mol in some embodiments, from 31,000 to 36,000 g/molin some embodiments.

In embodiments described herein, the polyethylene composition has weightaverage molecular weight (M_(w)) from 110,000 to 140,000 g/mol, from115,000 to 135,000 g/mol in some embodiments, from 118,000 to 130,000g/mol in some embodiments.

In embodiments described herein, the polyethylene composition hasz-average molecular weight (M_(t)) from 380,000 to 450,000 g/mol, from390,000 to 440,000 g/mol in some embodiments, from 395,000 to 435,000g/mol in some embodiments.

In embodiments described herein, the polyethylene composition hasM_(z)/M_(w) (ratio of z-average molecular weight (M_(z)) to weightaverage molecular weight (M_(w))) from 2.0 to 5.0, from 3.0 to 4.0 insome embodiments, from 3.2 to 3.5 in some embodiments.

In embodiments described herein, the polyethylene composition hasM_(z)/M_(n) (ratio of z-average molecular weight (M_(z)) to numberaverage molecular weight (M_(n))) from 10.0 to 14.0, from 11.0 to 13.5in some embodiments, from 11.5 to 13.0 in some embodiments.

In embodiments described herein, the polyethylene composition has a meltstrength in cN at 190° C. from 2.0 to 6.0, from 3.0 to 5.0 in someembodiments, from 3.0 to 4.0 in some embodiments.

In embodiments described herein, the polyethylene composition has wt %of Zone 1 from CEF from 1.0 to 6.0, from 2.0 to 5.0 in some embodiments,3.0 to 4.8 in some embodiments.

In embodiments described herein, the polyethylene composition has wt %of Zone 2 from CEF from 65.0 to 85.0, from 70.0 to 80.0 in someembodiments, from 71.0 to 80.0 in some embodiments.

In embodiments described herein, the polyethylene composition has wt %of Zone 3 from CEF from 15.0 to 30.0, from 15.0 to 27.0 in someembodiments, from 16.0 to 26.0 in some embodiments.

In embodiments described herein, the polyethylene composition has CBDIfrom CEF from 35.0 to 55.0, from 38.0 to 53.0 in some embodiments, from40.0 to 52.0 in some embodiments.

In embodiments described herein, the polyethylene composition hasViscosity Ratio at 190° C. from DMS from 3.0 to 7.0, from 3.5 to 6.0 insome embodiments, from 4.5 to 5.5 in some embodiments.

In embodiments described herein, the polyethylene composition has TanDelta at 0.1 rad/s at 190° C. from DMS from 5.0 to 15.0, from 6.0 to13.0 in some embodiments, from 8.0 to 12.0 in some embodiments.

In embodiments described herein, the polyethylene composition hashighest peak melting point (T_(m1)) from DSC in ° C. from 115.0 to130.0, from 117.0 to 128.0 in some embodiments, from 118.0 to 125.0 insome embodiments.

In embodiments described herein, the polyethylene composition hashighest peak crystallization point (T_(c1)) from DSC in ° C. from 100.0to 120.0, from 105.0 to 115.0 in some embodiments, from 107.0 to 110.0in some embodiments.

In embodiments described herein, the polyethylene composition has apercent crystallinity from DSC from 40.0 to 60.0, from 43.0 to 55.0 insome embodiments, from 45.0 to 50.0 in some embodiments.

In embodiments described herein, the polyethylene composition has avinyl unsaturation of greater than 0.12 vinyls per one thousand carbonatoms (“1000 C”). All individual values and subranges from greater than0.12 vinyls per 1000 carbon atoms are included and disclosed herein. Insome embodiments, the polyethylene composition may have greater than orequal to 0.13, 0.14, 0.15, or 0.16 vinyls per 1000 carbon atoms. Inother embodiments, the polyethylene composition may have vinyls per 1000carbon atoms ranging from a lower limit of greater than 0.12, 0.13,0.14, 0.15, 0.16, or 0.17 to an upper limit of 0.50, 0.45, 0.40, 0.35,0.30, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, or 0.20. In furtherembodiments, the polyethylene composition may have greater than 0.12 to0.50, 0.13 to 0.45, 0.14 to 0.40, 0.14 to 0.35, 0.14 to 0.30, 0.14 to0.25, or 0.15 to 0.22 vinyls per 1000 carbon atoms.

The layer in the film comprising the polyethylene composition, in someembodiments, further comprises a low density polyethylene (LDPE). Thefilm layer may comprise 50% or less by weight of the LDPE, based on theweight of the film layer, in some embodiments. In some embodiments, thefilm layer comprises from 5 to 30 wt. %, based on the total weight ofpolymers present in the film layer, of a LDPE. All individual values andsubranges from 5 to 30 wt. % are included and disclosed herein. Forexample, in some embodiments, the film layer may comprise from 10 to 30wt. %, based on the total weight of polymers present in the film layer,of a LDPE. In other embodiments, the film layer may comprise from 10 to25 wt. %, based on the total weight of polymers present in the filmlayer, of a LDPE. In further, embodiments, the film layer may comprisefrom 10 to 20 wt. %, based on the total weight of polymers present inthe film layer, of a LDPE.

In embodiments herein, the LDPE present may have a density of about0.915-0.935 g/cm³. All individual values and subranges from 0.915-0.935g/cm³ are included and disclosed herein. For example, in someembodiments, the LDPE has a density of 0.915-0.930 g/cm³. In otherembodiments, the LDPE has a density of 0.915-0.925 g/cm³. In embodimentsherein, the LDPE may have a melt index, I₂, of 0.1-20 g/10 min. Allindividual values and subranges from 0.1-20 g/10 min are included anddisclosed herein. For example, in some embodiments, the LDPE has a meltindex, I₂, of 0.5 to 20 g/10 min, 0.5 to 18 g/10 min, 0.5 to 16 g/10min, 0.5 to 14 g/10 min, 0.5 to 12 g/10 min, 0.1 to 5 g/10 min, or 0.5to 10 g/10 min. In other embodiments, the LDPE has a melt index, I₂, of1 to 20 g/10 min, 1 to 18 g/10 min, 1 to 16 g/10 min, 1 to 14 g/10 min,1 to 12 g/10 min, 0.1 to 4 g/10 min, or 1 to 10 g/10 min.

The term LDPE may also be used to refer to “high pressure ethylenepolymer” or “highly branched polyethylene,” and may include branchedpolymers that are partly or entirely homopolymerized or copolymerized inautoclave or tubular reactors at pressures above 14,500 psi (100 MPa)with the use of free-radical initiators, such as peroxides (see forexample U.S. Pat. No. 4,599,392, incorporated herein by reference).Examples of suitable LDPEs may include, but are not limited to, ethylenehomopolymers, and high pressure copolymers, including ethyleneinterpolymerized with, for example, vinyl acetate, ethyl acrylate, butylacrylate, acrylic acid, methacrylic acid, carbon monoxide, orcombinations thereof. Exemplary LDPE resins may include resins sold byThe Dow Chemical Company, such as, LDPE 722, LDPE 6401, LDPE 1321, LDPE230N, LDPE 586A, and LDPE 6211, as well as EB873/72 LDPE resincommercially available from Braskem.

In some embodiments, minor amounts of other polymers can also beincluded in the film layer comprising the polyethylene composition andthe LDPE. Examples of such other polymers include, without limitation,polyethylene (homopolymers or copolymers), polypropylene (homopolymersor copolymers), cyclic olefin copolymers, and others.

It should be understood that this layer, as well as any other layer whenthe film is a multilayer film, can further comprise one or moreadditives as known to those of skill in the art such as, for example,antioxidants, ultraviolet light stabilizers, thermal stabilizers, slipagents, antiblock, pigments or colorants, processing aids, crosslinkingcatalysts, flame retardants, fillers and foaming agents.

As previously indicated, in some embodiments, the film can be amultilayer film. In such embodiments, any additional layers would be inadhering contact with a top facial surface or a bottom facial surface ofthe layer with the polyethylene composition, or another intermediatelayer. For example, a multilayer film can further comprise other layerstypically included in multilayer films depending on the applicationincluding, for example, printed layers, sealant layers, barrier layers,tie layers, other polyethylene layers, etc.

Films of the present invention can be formed using techniques known tothose of skill in the art based on the teachings herein. For example,such films can be extruded (or coextruded in the case of multilayerfilms) as blown films or cast films using techniques known to those ofskill in the art based on the teachings herein.

Films of the present invention can be used to form an article. Films ofthe present invention might be particularly useful in articles thatrequire a film with high dart, puncture and/or tear resistanceproperties. Such articles can be formed from any of the films describedherein. Examples of such articles can include flexible packages such aspouches, stand-up pouches, and pre-made packages or pouches. In someembodiments, multilayer films of the present invention can be used forfood packages. Examples of food that can be included in such packagesinclude meats, cheeses, cereal, nuts, juices, sauces, and others. Suchpackages can be formed using techniques known to those of skill in theart based on the teachings herein and based on the particular use forthe package (e.g., type of food, amount of food, etc.).

Flexible packages utilizing films of the present invention canadvantageously be formed with heat seal packaging equipment utilizingcontinuously heated seal bars, in some embodiments. Examples of suchpackaging equipment utilizing continuously heated seal bars includehorizontal form-fill-seal machines and vertical form-fill-seal machines.Examples of packages that can be formed from such equipment includestand-up pouches, 4-corner packages (pillow pouches), fin seal packagesand others.

Test Methods

Density

Samples for density measurements were prepared according to ASTM D4703-10 Annex A1 Procedure C. Approximately 7 g of sample was placed ina “2″×2″×135 mil thick” mold, and this was pressed at 374° F. (190° C.)for six minutes at 3,000 lbf (0.0133 MN). Then the pressure wasincreased to 30,000 lbf (0.133 MN) for four minutes. This was followedby cooling at 15° C. per minute, at 30,000 lbf (0.133 MN), toapproximately a temperature of 40° C. The “2″×2″×135 mil” polymer sample(plaque) was then removed from the mold, and three samples were cut fromthe plaque with a ½″×1″ die cutter. Density measurements were madewithin one hour of sample pressing, using ASTM D792-08, Method B.Density was reported as an average of three measurements.

Melt Index

Melt index (I₂) can be measured in accordance with ASTM D-1238,Procedure B (condition 190° C./2.16 kg). Melt index (I₁₀) can bemeasured in accordance with ASTM D-1238, Procedure B (condition 190°C./10.0 kg).

Gel Permeation Chromatography (GPC)

The chromatographic system consisted of a PolymerChar GPC-IR (Valencia,Spain) high temperature GPC chromatograph equipped with an internal IR5detector. The autosampler oven compartment was set at 160° Celsius andthe column compartment was set at 150° Celsius. The columns used were 3Agilent “Mixed B” 30 cm 10-micron linear mixed-bed columns and a 10-μmpre-column. The chromatographic solvent used was 1,2,4 trichlorobenzeneand contained 200 ppm of butylated hydroxytoluene (BHT). The solventsource was nitrogen sparged. The injection volume used was 200microliters and the flow rate was 1.0 milliliters/minute.

Calibration of the GPC column set was performed with 21 narrow molecularweight distribution polystyrene standards with molecular weights rangingfrom 580 to 8,400,000 and were arranged in 6 “cocktail” mixtures with atleast a decade of separation between individual molecular weights. Thestandards were purchased from Agilent Technologies. The polystyrenestandards were prepared at 0.025 grams in 50 milliliters of solvent formolecular weights equal to or greater than 1,000,000, and 0.05 grams in50 milliliters of solvent for molecular weights less than 1,000,000. Thepolystyrene standards were dissolved at 80 degrees Celsius with gentleagitation for 30 minutes. The polystyrene standard peak molecularweights were converted to polyethylene molecular weights using Equation1 (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6,621 (1968)):M _(polyethylene) =A×(M _(polystyrene))^(B)  (EQ1)where M is the molecular weight, A has a value of 0.4315 and B is equalto 1.0.

A fifth order polynomial was used to fit the respectivepolyethylene-equivalent calibration points. A small adjustment to A(from approximately 0.415 to 0.44) was made to correct for columnresolution and band-broadening effects such that NIST standard NBS 1475is obtained at 52,000 g/mol Mw.

The total plate count of the GPC column set was performed with Eicosane(prepared at 0.04 g in 50 milliliters of TCB and dissolved for 20minutes with gentle agitation.) The plate count (Equation 2) andsymmetry (Equation 3) was measured on a 200 microliter injectionaccording to the following equations:

$\begin{matrix}{{Plate}\mspace{14mu}{Count}{= {{5.5}4*( \frac{{RV}_{{Peak}\mspace{14mu}{Max}}}{{Peak}\mspace{14mu}{Width}\mspace{14mu}{at}\frac{1}{2}{height}} )^{2}}}} & ({EQ2})\end{matrix}$where RV is the retention volume in milliliters, the peak width is inmilliliters, the peak max is the maximum height of the peak, and ½height is ½ height of the peak maximum.

$\begin{matrix}{{Symmetry} = \frac{( {{{Rear}\mspace{14mu}{Peak}\mspace{14mu}{RV}_{{one}\mspace{14mu}{tenth}\mspace{14mu}{height}}} - {RV}_{{Peak}\mspace{14mu}\max}} )}{( {{RV}_{{Peak}\mspace{14mu}\max} - {{Front}\mspace{14mu}{Peak}\mspace{14mu}{RV}_{{one}\mspace{14mu}{tenth}\mspace{14mu}{height}}}} )}} & ({EQ3})\end{matrix}$where RV is the retention volume in milliliters and the peak width is inmilliliters, peak max is the maximum position of the peak, one tenthheight is 1/10 height of the peak maximum, rear peak refers to the peaktail at later retention volumes than the peak max, and front peak refersto the peak front at earlier retention volumes than the peak max. Theplate count for the chromatographic system should be greater than 24,000and symmetry should be between 0.98 and 1.22.

Samples were prepared in a semi-automatic manner with the PolymerChar“Instrument Control” Software, wherein the samples were weight-targetedat 2 mg/ml, and the solvent (contained 200 ppm BHT) was added to a prenitrogen-sparged septa-capped vial, via the PolymerChar high temperatureautosampler. The samples were dissolved for 2 hours at 160° Celsiusunder “low speed” shaking.

The calculations of M_(n), M_(w), and M_(z) were based on GPC resultsusing the internal IR5 detector (measurement channel) of the PolymerCharGPC-IR chromatograph according to Equations 4-6, using PolymerCharGPCOne™ software, the baseline-subtracted IR chromatogram at eachequally-spaced data collection point (i), and the polyethyleneequivalent molecular weight obtained from the narrow standardcalibration curve for the point (i) from Equation 1.

$\begin{matrix}{M_{n} = \frac{\sum\limits^{i}\;{IR}_{i}}{\sum\limits^{i}\;( {{IR}_{i}/M_{{polyethylene}_{\; i}}^{\;}} )}} & ({EQ4}) \\{M_{w} = \frac{\sum\limits^{i}\;( {{IR}_{i}*M_{{polyethylene}_{\; i}}} )}{\sum\limits^{i}{IR}_{i}}} & ({EQ5}) \\{M_{z} = \frac{\sum\limits^{i}\;( {{IR}_{i}*M_{{polyethylene}_{\; i}}^{2}} )}{\sum\limits^{i}\;( {{IR}_{i}*M_{{polyethylene}_{\; i}}^{\;}} )}} & ({EQ6})\end{matrix}$

In order to monitor the deviations over time, a flowrate marker (decane)was introduced into each sample via a micropump controlled with thePolymerChar GPC-IR system. This flowrate marker was used to linearlycorrect the flowrate for each sample by alignment of the respectivedecane peak within the sample to that of the decane peak within thenarrow standards calibration. Any changes in the time of the decanemarker peak are then assumed to be related to a linear shift in bothflowrate and chromatographic slope. To facilitate the highest accuracyof a RV measurement of the flow marker peak, a least-squares fittingroutine is used to fit the peak of the flow marker concentrationchromatogram to a quadratic equation. The first derivative of thequadratic equation is then used to solve for the true peak position.After calibrating the system based on a flow marker peak, the effectiveflowrate (as a measurement of the calibration slope) is calculated asEquation 7. Processing of the flow marker peak was done via thePolymerChar GPCOne™ Software.

$\begin{matrix}{{Flowrate_{effective}} = {Flowrate_{nominal} \times \frac{FlowMarker_{Calibration}}{FlowMarker_{Observed}}}} & ({EQ7})\end{matrix}$Neutron Activation Method for Metals

Two sets of duplicate samples were prepared by transferringapproximately 3.5 grams of the pellets into pre-cleaned 2 drampolyethylene vials. Standards were prepared for each metal tested fromtheir NIST traceable standard solutions (Certi. pure from SPEX) into2-dram polyethylene vials. They were diluted using milli-Q pure water to6 ml and the vials were heat-sealed. The samples and standards were thenanalyzed for these elements, using a Mark I TRIGA nuclear reactor. Thereactions and experimental conditions used for these elements aresummarized in the table below. The samples were transferred toun-irradiated vials before doing the gamma-spectroscopy. The elementalconcentrations were calculated using CANBERRA software and standardcomparative technique. Table 1 provides measurement parameters formetals determination.

TABLE 1 Reactions and experimental conditions used for elements duringthe neutron activation method Elements Nuclear reaction Isotope Halflife Reactor Power Al ²⁷Al(n, γ)²⁸Al ²⁸Al 2.24 m 250 kW Cl ³⁷Cl(n,γ)³⁸Cl ³⁸Cl 37.2 m 250 kW Cr ⁵⁰Cr(n, γ)⁵¹Cr ⁵¹Cr 27.7 d 250 kW Hf¹⁸⁰Hf(n, γ)¹⁸¹Hf ¹⁸¹Hf 42.4 d 250 kW Mg ²⁶Mg(n, γ)²⁷Mg ²⁷Mg 9.46 m 250kW Mo ⁹⁸Mo(n, γ)⁹⁹Mo ⁹⁹Mo 66.0 h 250 kW Nb ⁹³Nb(n, γ)^(94m)Nb ^(94m)Nb6.26 m 250 kW Ta ¹⁸¹Ta(n, γ)¹⁸²Ta ¹⁸²Ta 114.4 d 250 kW Ti ⁵⁰Ti(n, γ)⁵¹Ti⁵¹Ti 5.76 m 250 kW W ¹⁸⁶W(n, γ)¹⁸⁷W ¹⁸⁷W 23.7 h 250 kW V ⁵¹V(n, γ)⁵²V⁵²V 3.75 m 250 kW Zr ⁹⁶Zr(n, γ)⁹⁷Zr ⁹⁷Zr 16.91 h 250 kW Waiting CountingGamma Energy, Elements Irradiation Time Time Time keV Al  2 m 4 m 4.5min 1778.5 Cl  2 m 4 m 4.5 min 1642.5, 2166.5 Cr 90 m 5 h 1.6 h  320 Hf90 m 5 h 1.6 h 133, 482 Mg  2 m 4 m 4.5 min 843.8, 1014 Mo 90 m 5 h 1.6h 181, 739.7, 141 Nb  2 m 4 m 4.5 min  871 Ta 90 m 5 h 1.6 h 1121, 1222Ti  2 m 4 m 4.5 min  320 W 90 m 5 h 1.6 h 135, 481 V  2 m 4 m 4.5 min1434 Zr 90 m 5 h 1.6 h  743.4Differential Scanning calorimetry (DSC)

DSC was used to measure the melting and crystallization behavior of apolymer over a wide range of temperatures. For example, the TAInstruments Q1000 DSC, equipped with an RCS (refrigerated coolingsystem) and an autosampler was used to perform this analysis. Duringtesting, a nitrogen purge gas flow of 50 ml/min was used. Each samplewas melt pressed into a thin film at about 175° C.; the melted samplewas then air-cooled to room temperature (approx. 25° C.). The filmsample was formed by pressing a “0.1 to 0.2 gram” sample at 175° C. at1,500 psi, and 30 seconds, to form a “0.1 to 0.2 mil thick” film. A 3-10mg, 6 mm diameter specimen was extracted from the cooled polymer,weighed, placed in a light aluminum pan (ca 50 mg), and crimped shut.Analysis was then performed to determine its thermal properties.

The thermal behavior of the sample was determined by ramping the sampletemperature up and down to create a heat flow versus temperatureprofile. First, the sample was rapidly heated to 180° C., and heldisothermal for five minutes, in order to remove its thermal history.Next, the sample was cooled to −40° C., at a 10° C./minute cooling rate,and held isothermal at −40° C. for five minutes. The sample was thenheated to 150° C. (this is the “second heat” ramp) at a 10° C./minuteheating rate. The cooling and second heating curves were recorded. Thecool curve was analyzed by setting baseline endpoints from the beginningof crystallization to −20° C. The heat curve was analyzed by settingbaseline endpoints from −20° C. to the end of melt. The valuesdetermined were peak melting temperature (T_(m)), peak crystallizationtemperature (TO, heat of fusion (H_(f)) (in Joules per gram), and thecalculated % crystallinity for polyethylene samples using: %Crystallinity=((H_(f))/(292 J/g))×100. The heat of fusion (H_(f)) andthe peak melting temperature were reported from the second heat curve.Peak crystallization temperature is determined from the cooling curve.

Melt Strength

Melt strength was measured at 190° C. using a Göettfert Rheotens 71.97(Göettfert Inc.; Rock Hill, S.C.), melt fed with a Göettfert Rheotester2000 capillary rheometer equipped with a flat entrance angle (180degrees) of length of 30 mm and diameter of 2.0 mm. The pellets (20-30gram pellets) were fed into the barrel (length=300 mm, diameter=12 mm),compressed and allowed to melt for 10 minutes before being extruded at aconstant piston speed of 0.265 mm/s, which corresponds to a wall shearrate of 38.2 s⁻¹ at the given die diameter. The extrudate passed throughthe wheels of the Rheotens located 100 mm below the die exit and waspulled by the wheels downward at an acceleration rate of 2.4 mm/s². Theforce (in cN) exerted on the wheels was recorded as a function of thevelocity of the wheels (in mm/s). Melt strength is reported as theplateau force (cN) before the strand broke.

Dynamic Mechanical Spectroscopy (DMS)

Resins were compression-molded into “3 mm thick×1 inch diameter”circular plaques at 350° F., for five minutes, under 1500 psi pressure,in air. The sample was then taken out of the press, and placed on acounter to cool.

A constant temperature frequency sweep was performed using a TAInstruments “Advanced Rheometric Expansion System (ARES),” equipped with25 mm (diameter) parallel plates, under a nitrogen purge. The sample wasplaced on the plate, and allowed to melt for five minutes at 190° C. Theplates were then closed to a gap of “2 mm,” the sample trimmed (extrasample that extends beyond the circumference of the “25 mm diameter”plate was removed), and then the test was started. The method had anadditional five minute delay built in, to allow for temperatureequilibrium. The experiments were performed at 190° C. over a frequencyrange of 0.1 to 100 rad/s. The shear strain amplitude was constant at10%. The complex viscosity η*, tan (δ) or tan delta, viscosity at 0.1rad/s (V0.1), the viscosity at 100 rad/s (V100), and the viscosity ratio(V0.1/V100) were calculated from these data.

Crystallization Elution Fractionation (CEF) Method

The Crystallization Elution Fractionation (CEF) technology is conductedaccording to Monrabal et al, Macromol. Symp. 257, 71-79 (2007). The CEFinstrument is equipped with an IR-4 or IR-5 detector (such as that soldcommercially from PolymerChar, Spain) and a two angle light scatteringdetector Model 2040 (such as those sold commercially from PrecisionDetectors). A 10 micron guard column of 50 mm×4.6 mm (such as that soldcommercially from PolymerLabs) is installed before the IR-4 or IR-5detector in the detector oven. Ortho-dichlorobenzene (ODCB, 99%anhydrous grade) and 2,5-di-tert-butyl-4-methylphenol (BHT) (such ascommercially available from Sigma-Aldrich) are obtained. Silica gel 40(particle size 0.2-0.5 mm) (such as commercially available from EMDChemicals) is also obtained. The silica gel is dried in a vacuum oven at160° C. for at least two hours before use. ODCB is sparged with driednitrogen (N₂) for one hour before use. Dried nitrogen is obtained bypassing nitrogen at <90 psig over CaCO₃ and 5 Å molecular sieves. ODCBis further dried by adding five grams of the dried silica to two litersof ODCB or by pumping through a column or columns packed with driedsilica between 0.1 ml/min to 1.0 ml/min. Eight hundred milligrams of BHTare added to two liters of ODCB if no inert gas such as N₂ is used inpurging the sample vial. Dried ODCB with or without BHT is hereinafterreferred to as “ODCB-m.” A sample solution is prepared by, using theautosampler, dissolving a polymer sample in ODCB-m at 4 mg/ml undershaking at 160° C. for 2 hours. 300 μL of the sample solution isinjected into the column. The temperature profile of CEF is:crystallization at 3° C./min from 110° C. to 30° C., thermal equilibriumat 30° C. for 5 minutes (including Soluble Fraction Elution Time beingset as 2 minutes), and elution at 3° C./min from 30° C. to 140° C. Theflow rate during crystallization is 0.052 ml/min. The flow rate duringelution is 0.50 ml/min. The IR-4 or IR-5 signal data is collected at onedata point/second.

The CEF column is packed with glass beads at 125 μm±6% (such as thosecommercially available with acid wash from MO-SCI Specialty Products)with ⅛ inch stainless tubing according to U.S. Pat. No. 8,372,931. Theinternal liquid volume of the CEF column is between 2.1 ml and 2.3 ml.Temperature calibration is performed by using a mixture of NIST StandardReference Material linear polyethylene 1475a (1.0 mg/ml) and Eicosane (2mg/ml) in ODCB-m. The calibration consists of four steps: (1)calculating the delay volume defined as the temperature offset betweenthe measured peak elution temperature of Eicosane minus 30.00° C.; (2)subtracting the temperature offset of the elution temperature from theCEF raw temperature data. It is noted that this temperature offset is afunction of experimental conditions, such as elution temperature,elution flow rate, etc.; (3) creating a linear calibration linetransforming the elution temperature across a range of 30.00° C. and140.00° C. such that NIST linear polyethylene 1475a has a peaktemperature at 101.00° C., and Eicosane has a peak temperature of 30.00°C., (4) for the soluble fraction measured isothermally at 30° C., theelution temperature is extrapolated linearly by using the elutionheating rate of 3° C./min. The reported elution peak temperatures areobtained such that the observed comonomer content calibration curveagrees with those previously reported in U.S. Pat. No. 8,372,931.

The CEF chromatogram is divided into zones, the elution temperaturerange of each zone is specified.

Comonomer Distribution Breadth Index (CDBI)

The CDBI is calculated using the methodology described in WO/93/03093from data obtained from CEF. CDBI is defined as the weight percent ofthe polymer molecules having a comonomer content within 50 percent ofthe median total molar comonomer content. It represents a comparison ofthe comonomer distribution in the polymer to the comonomer distributionexpected for a Bernoullian distribution.

CEF is used to measure the short chain branching distribution (SCBD) ofthe polyolefin. A CEF molar comonomer content calibration is performedusing 24 reference materials (e.g., polyethylene octene random copolymerand ethylene butene copolymer) with a narrow SCBD having a comonomermole fraction ranging from 0 to 0.108 and a Mw from 28,400 to 174,000g/mole. The ln (mole fraction of ethylene), which is the ln (comonomermole fraction), versus 1/T (K) is obtained, where T is the elutiontemperature in Kelvin of each reference material. The comonomerdistribution of the reference materials is determined using 13C NMRanalysis in accordance with techniques described, for example, in U.S.Pat. No. 5,292,845 (Kawasaki, et al.) and by J. C. Randall in Rev.Macromol. Chem. Phys., C29, 201-317.

Nuclear Magnetic Resonance (¹H NMR)

The samples were prepared by adding approximately 130 mg of sample to“3.25 g of 50/50, by weight, tetrachlorethane-d₂/perchloroethylene(TCE-d₂)” with 0.001 M Cr(AcAc)₃ in a NORELL 1001-7, 10 mm NMR tube. Thesamples were purged by bubbling N₂ through the solvent, via a pipetteinserted into the tube, for approximately five minutes, to preventoxidation. Each tube was capped, sealed with TEFLON tape, and thensoaked at room temperature, overnight, to facilitate sample dissolution.The samples were heated and vortexed at 115° C. to ensure homogeneity.

The ¹H NMR was performed on a Bruker AVANCE 400 MHz spectrometer,equipped with a Bruker Dual DUL high-temperature CryoProbe, and a sampletemperature of 120° C. Two experiments were run to obtain spectra, acontrol spectrum to quantitate the total polymer protons, and a doublepresaturation experiment, which suppressed the intense polymer backbonepeaks, and enabled high sensitivity spectra for quantitation of theend-groups. The control was run with ZG pulse, 16 scans, AQ 1.64 s, D114 s. The double presaturation experiment was run with a modified pulsesequence, 100 scans, AQ 1.64 s, presaturation delay 1 s, relaxationdelay 13 s.

The signal from residual ¹H in TCE-d₂ (at 6.0 ppm) was integrated, andset to a value of 100, and the integral from 3 to −0.5 ppm was used asthe signal from the whole polymer in the control experiment. For thepresaturation experiment, the TCE signal was also set to 100, and thecorresponding integrals for unsaturation (vinylene at about 5.25 to 5.60ppm, trisubstituted at about 5.16 to 5.25 ppm, vinyl at about 4.95 to5.15 ppm, and vinylidene at about 4.70 to 4.90 ppm) were obtained.

In the presaturation experiment spectrum, the regions for cis- andtrans-vinylene, trisubstituted, vinyl, and vinylidene were integrated.The integral of the whole polymer from the control experiment wasdivided by two to obtain a value representing X thousands of carbons(i.e., if the polymer integral=28000, this represents 14,000 carbons,and X=14).

The unsaturated group integrals, divided by the corresponding number ofprotons contributing to that integral, represent the moles of each typeof unsaturation per X thousand carbons. Dividing the moles of each typeof unsaturation by X, then gives moles unsaturated groups per 1000 molesof carbons.

Film Property Test Methods

Dart Drop Test

The film Dart Drop test determines the energy that causes a plastic filmto fail, under specified conditions of impact by a free falling dart.The test result is the Dart Impact which reflects the energy, expressedin terms of the weight of the missile falling from a specified height,which would result in the failure of 50% of the specimens tested.

After the film was produced on the blown film line, it was conditionedfor at least 40 hours at 23° C. (+/−2° C.) and 50% R.H (+/−5), as perASTM standards. Standard testing conditions are 23° C. (+/−2° C.) and50% R.H (+/−5), as per ASTM standards.

The test result was reported as either by Method A, which uses a 1.5″diameter dart head and 26″ drop height, or by Method B, which uses a 2″diameter dart head and 60″ drop height. The sample thickness wasmeasured at the sample center, and the sample was then clamped by anannular specimen holder with an inside diameter of 5 inches. The dartwas loaded above the center of the sample, and released by either apneumatic or electromagnetic mechanism.

Testing was carried out according to the ‘staircase’ method. If thesample failed, a new sample was tested with the weight of the dartreduced by a known and fixed amount. If the sample did not fail, a newsample was tested with the weight of the dart increased by a knownamount. After 20 specimens had been tested, the number of failures wasdetermined. If this number was 10, then the test is complete. If thenumber was less than 10, then the testing continued, until 10 failureshad been recorded. If the number was greater than 10, testing wascontinued, until the total of non-failures was 10. The Dart DropStrength was determined from these data, as per ASTM D1709, andexpressed in grams, as either the Dart Drop Impact of Type A or Type B.In some cases, the sample Dart Drop Impact strength may lie between Aand B. In these cases, it is not possible to obtain a quantitative dartvalue.

Puncture

Puncture is measured using ASTM D5748, except that the probe used is0.5″ in diameter and is stainless steel. Speed=250 mm/min.

Elmendorf Tear

Elmendorf tear test data is measured on all films in accordance withASTM D1922-09. All samples are tested in the machine direction (MD) andthe cross-direction (CD). 15 specimens per each sample are tested andthe average value is recorded.

EXAMPLES

A multi-metal catalyst is prepared (Catalyst 1). Catalyst 1 is then usedto prepare an inventive polyethylene composition in a solutionpolymerization. Subsequently, the inventive and comparative polyethylenecompositions are used to prepare inventive and comparative blown films,respectively. Testing is carried out on both the polyethylenecompositions and the blown films.

General Description of Preparation of Catalysts

The catalyst compositions may be prepared beginning first withpreparation of a conditioned magnesium halide based support. Preparationof a conditioned magnesium halide based support begins with selecting anorganomagnesium compound or a complex including an organomagnesiumcompound. Such compound or complex is desirably soluble in an inerthydrocarbon diluent. In one embodiment, the concentrations of componentsare such that when the active halide, such as a metallic or non-metallichalide, and the magnesium complex are combined, the resultant slurry isfrom about 0.005 to about 0.3 molar (moles/liter) with respect tomagnesium. Examples of suitable inert organic diluents include liquefiedethane, propane, isobutane, n-butane, n-hexane, the various isomerichexanes, isooctane, paraffinic mixtures of alkanes having from 5 to 10carbon atoms, cyclohexane, methylcyclopentane, dimethylcyclohexane,dodecane, industrial solvents composed of saturated or aromatichydrocarbons such as kerosene, naphthas, and combinations thereof,especially when freed of any olefin compounds and other impurities, andespecially those having boiling points in the range from about −50° C.to about 200° C. Also included as suitable inert diluents areethylbenzene, cumene, decalin and combinations thereof.

Suitable organomagnesium compounds and complexes may include, forexample, magnesium C2-C8 alkyls and aryls, magnesium alkoxides andaryloxides, carboxylated magnesium alkoxides, and carboxylated magnesiumaryloxides. Preferred sources of magnesium moieties may include themagnesium C2-C8 alkyls and C1-C4 alkoxides. Such organomagnesiumcompound or complex may be reacted with a metallic or non-metallichalide source, such as a chloride, bromide, iodide, or fluoride, inorder to make a magnesium halide compound under suitable conditions.Such conditions may include a temperature ranging from −25° C. to 100°C., or alternatively, 0° C. to 50° C.; a time ranging from 1 to 12hours, or alternatively, from 4 to 6 hours; or both. The result is amagnesium halide-based support.

The magnesium halide support is then reacted with a selectedconditioning compound containing an element selected from the groupconsisting of boron, aluminum, gallium, indium and tellurium, underconditions suitable to form a conditioned magnesium halide support. Thiscompound and the magnesium halide support are then brought into contactunder conditions sufficient to result in a conditioned magnesium halidesupport. Such conditions may include a temperature ranging from 0° C. to50° C., or alternatively, from 25° C. to 35° C.; a time ranging from 4to 24 hours, or alternatively, from 6 to 12 hours; or both. Withoutwishing to be bound by any theory of mechanism, it is suggested thatthis aging serves to facilitate or enhance adsorption of additionalmetals onto the support.

Once the conditioned support is prepared and suitably aged, it isbrought into contact with a titanium compound. In certain preferredembodiments, titanium halides or alkoxides, or combinations thereof, maybe selected. Conditions may include a temperature within the range from0° C. to 50° C., or alternatively, from 25° C. to 35° C.; a time from 3hours to 24 hours, or alternatively, from 6 hours to 12 hours; or both.The result of this step is adsorption of at least a portion of thetitanium compound onto the conditioned magnesium halide support.

Additional Steps in Preparing Multi-Metal Catalyst Used to Make theInventive Polyethylene Composition

For those catalysts used to make the inventive polyethylene composition,i.e. multi-metal catalysts herein, two additional metals, referred toherein as “the second metal” and “the third metal” for convenience, willalso be adsorbed onto the magnesium based support, The “second metal”and the “third metal” are independently selected from zirconium (Zr),hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr),molybdenum (Mo), and tungsten (W). These metals may be incorporated inany of a variety of ways known to those skilled in the art, butgenerally contact between the conditioned magnesium based halide supportincluding titanium and the selected second and third metals, in, e.g.,liquid phase such as an appropriate hydrocarbon solvent, will besuitable to ensure deposition of the additional metals to form what maynow be referred to as the “procatalyst,” which is a multi-metallicprocatalyst.

In certain embodiments, the multi-metal procatalyst exhibits a molarratio of the magnesium to a combination of the titanium and the secondand third metals that ranges from 30:1 to 5:1; under conditionssufficient to form a multi-metallic procatalyst. Thus, the overall molarratio of magnesium to titanium ranges from 8:1 to 80:1.

Once the procatalyst has been formed, it may be used to form a finalcatalyst by combining it with a cocatalyst consisting of at least oneorganometallic compound such as an alkyl or haloalkyl of aluminum, analkylaluminum halide, a Grignard reagent, an alkali metal aluminumhydride, an alkali metal borohydride, an alkali metal hydride, analkaline earth metal hydride, or the like. The formation of the finalcatalyst from the reaction of the procatalyst and the organometalliccocatalyst may be carried out in situ, or just prior to entering thepolymerization reactor. Thus, the combination of the cocatalyst and theprocatalyst may occur under a wide variety of conditions. Suchconditions may include, for example, contacting them under an inertatmosphere such as nitrogen, argon or other inert gas at temperatures inthe range from 0° C. to 250° C., or alternatively, from 15° C. to 200°C. In the preparation of the catalytic reaction product, it is notnecessary to separate hydrocarbon soluble components from hydrocarboninsoluble components. Time for contact between the procatalyst andcocatalyst may range, for example, from 0 to 240 seconds, oralternatively, from 5 to 120 seconds. Various combinations of theseconditions may be employed.

Catalyst I Preparation

To approximately 109 kg of 0.20 M MgCl₂ slurry was added 7.76 kg of(C₂H₅)AlCl₂ (EADC) solution (15 wt. % in heptanes), followed byagitation for 8 hours. A mixture of TiCl₄/VOCl₃ (85 mL and 146 mL,respectively) was then added, followed by a solution of Zr(TMHD)₄(Zirconium tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionate) (0.320 kg ofa 0.30 M solution in Isopar E). These two additions were performedsequentially within 1 hour of each other. The resulting catalyst premixwas aged with agitation for an additional 8 h prior to use.

Catalyst 1 prepared hereinabove is then used to prepare PolyethyleneCompositions as described below.

Production of Inventive Polyethylene Compositions

The polyethylene resins are produced via a solution polymerizationaccording to the following exemplary process. All raw materials (monomerand comonomer) and the process solvent (a narrow boiling rangehigh-purity isoparaffinic solvent, Isopar-E) are purified with molecularsieves before introduction into the reaction environment. Hydrogen issupplied in pressurized cylinders as a high purity grade and is notfurther purified. The reactor monomer feed stream is pressurized via amechanical compressor to above reaction pressure. The fresh comonomer ispressurized via a pump and injected into the solvent feed stream to thereactor. The solvent and comonomer feed is then pressurized via a pumpto above reaction pressure. The individual catalyst components aremanually batch diluted to specified component concentrations withpurified solvent and pressured to above reaction pressure. All reactionfeed flows are measured with mass flow meters and independentlycontrolled with computer automated valve control systems.

The continuous solution polymerization reactor consists of a liquidfull, non-adiabatic, isothermal, circulating, loop reactor which mimicsa continuously stirred tank reactor (CSTR) with heat removal.Independent control of all fresh solvent, monomer, comonomer, hydrogen,and catalyst component feeds is possible. The total fresh feed stream tothe reactor (solvent, monomer, comonomer, and hydrogen) is temperaturecontrolled by passing the feed stream through a heat exchanger. Thetotal fresh feed to the polymerization reactor is injected into thereactor at two locations with approximately equal reactor volumesbetween each injection location. The fresh feed is controlled with eachinjector receiving half of the total fresh feed mass flow. The catalystcomponents are injected into the polymerization reactor through aspecially designed injection stinger and are combined into one mixedcatalyst/cocatalyst feed stream prior to injection into the reactor. Theprimary catalyst component feed is computer controlled to maintain thereactor monomer concentration at a specified target. The cocatalystcomponent is fed based on calculated specified molar ratio to theprimary catalyst component. Immediately following each fresh injectionlocation (either feed or catalyst), the feed streams are mixed with thecirculating polymerization reactor contents with static mixing elements.The contents of the reactor are continuously circulated through heatexchangers responsible for removing much of the heat of reaction andwith the temperature of the coolant side responsible for maintaining anisothermal reaction environment at the specified temperature.Circulation around the reactor loop is provided by a positivedisplacement pump.

The final reactor effluent enters a zone where it is deactivated withthe addition of and reaction with water. At this same reactor exitlocation other additives may also be added (such as an acid scavengingagent and anti-oxidants). The stream then goes through a static mixer todisperse the post reactor additive components.

Following catalyst deactivation and additive addition, the reactoreffluent enters a devolatization system where the polymer is removedfrom the non-polymer stream. The isolated polymer melt is pelletized andcollected. The non-polymer stream passes through various pieces ofequipment which separate most of the ethylene which is removed from thesystem. Most of the solvent and unreacted comonomer is recycled back tothe reactor after passing through a purification system. A small amountof solvent and comonomer is purged from the process.

Table 2 summarizes the polymerization conditions for the InventivePolyethylene Compositions (IE). Additives used in these polymerizationsare 1250 ppm calcium stearate, 1000 ppm IRGAFOS 168 (which is tris (2,4di-tert-butylphenyl) phosphite), 250 ppm IRGANOX 1076 (which isoctadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate)), 200 ppmIRGANOX 1010 (which is Pentaerythritol Tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate)), and 300 ppmHydrotalcite, as well as conventional slip, antiblock and opticalbrighteners additives. IRGAFOS 168, IRGANOX 1010 and IRGANOX 1076 arecommercially available from BASF.

TABLE 2 Polymerization Conditions Sample IE 1 IE 2 IE 3 ReactorConfiguration Type Single Single Single Comonomer type Type 1-octene1-hexene 1-octene Reactor Feed Solvent / Ethylene Mass Flow Ratio g/g3.4 4.1 3.5 Reactor Feed Comonomer / Ethylene Mass Flow g/g 0.63 0.450.48 Ratio Reactor Feed Hydrogen / Ethylene Mass Flow Ratio g/g 1.0E−044.0E−05 5.2E−05 Reactor Temperature ° C. 175 190 192 Reactor Pressurebarg 50 50 50 Reactor Ethylene Conversion % 92.0 92.0 92.4 ReactorCatalyst Type Type Catalyst 1 Catalyst 1 Catalyst 1 Reactor Co-CatalystType Type TEA* TEA* TEA* Reactor Co-Catalyst to Catalyst Molar Ratio (Alto Ratio 12.0 10.0 11.0 Ti ratio) Reactor Residence Time Min 6.4 6.1 7.0*TEA is tri-ethyl-aluminum.

A variety of properties set forth in the below Tables are measured forIE1-IE3 as well as for three linear low density polyethylenes that arealso used to make the films. LLDPE1 is DOWLEX™ TG 2085B linear lowdensity polyethylene commercially available from The Dow ChemicalCompany. LLDPE2 is DOWLEX™ 2685G linear low density polyethylenecommercially available from The Dow Chemical Company. LLDPE3 is Flexus9211 metallocene-catalyzed linear low density polyethylene commerciallyavailable from Braskem.

TABLE 3 Comonomer, Measured Melt Index, and Density Data 12, g/10I10/I2, Density Sample Comonomer min g/10 min (g/cc) IE1 Octene 0.927.32 0.9200 IE2 Hexene 0.74 7.26 0.9185 IE3 Octene 1.00 7.37 0.9208LLDPE1 Octene 0.94 8.05 0.9197 LLDPE2 Hexene 0.72 8.27 0.9194 LLDPE3Hexene 1.01 5.75 0.9182

TABLE 4 Conventional GPC Data Mn Mw Mz Sample (g/mol) (g/mol) (g/mol)Mw/Mn Mz/Mw Mz/Mn IE1 32,416 119,968 396,896 3.70 3.31 12.24 IE2 35,375129,224 430,529 3.65 3.33 12.17 IE3 32,624 122,700 405,632 3.76 3.3112.43 LLDPE1 30,815 122,947 395,947 3.99 3.22 12.85 LLDPE2 31,000131,902 442,826 4.25 3.36 14.28 LLDPE3 43,501 107,777 194,006 2.48 1.804.46

TABLE 5 Melt Strength Data Velocity at Melt Break Strength Sample (mm/s)(cN) IE1 271 3.3 IE2 162 3.5 IE3 268 3.5 LLDPE1 277 3.5 LLDPE2 264 4.1LLDPE3 259 2.5

TABLE 6 CEF and CDBI Data Peak Temperature Range of Each PeakTemperature Zone (° C.) (° C.) Wt % of Each Zone Sample Zone 1 Zone 2Zone 3 Zone 1 Zone 2 Zone 3 Zone 1 Zone 2 Zone 3 CDBI IE1 25.0 to 34.534.6 to 94.1 94.2 to 120.0 28.5 85.0 98.9 4.4 75.6 20.1 45.7 IE2 25.0 to34.5 34.6 to 93.9 94.0 to 120.0 28.5 84.9 98.5 4.4 78.8 16.8 50.2 IE325.0 to 34.5 34.6 to 93.9 94.0 to 120.0 28.5 85.1 99.0 3.4 72.3 24.341.9 LLDPE1 25.1 to 32.0 32.0 to 92.5 92.6 to 120.0 28.4 83.2 98.7 5.269.3 25.6 40.6 LLDPE2 25.1 to 32.0 32.1 to 92.4  92.5to 120.0 28.5 82.697.8 6.0 76.7 17.3 52.0 LLDPE3 25.0 to 33.6  33.7 to 120.0 NA 28.5 84.5NA 0.7 99.3 NA 61.6 NA = Not Applicable

TABLE 7 DMS Rheology Data (at 190° C.) Viscosity (Pa-s) at 190 C.Viscosity Tan Delta Sample 0.1 rad/s 1 rad/s 10 rad/s 100 rad/s Ratio0.1 rad/s IE1 8,913 7,065 4,368 1,801 4.95 8.66 IE2 10,369 8,301 5,0792,035 5.10 9.33 IE3 8,399 6,840 4,311 1,798 4.67 10.08 LLDPE1 8,5686,864 4,138 1,655 5.18 9.64 LLDPE2 10,762 8,343 4,793 1,816 5.93 8.12LLDPE3 6,665 6,313 5,037 2,432 2.74 34.34

TABLE 8 DSC Data T_(m1) T_(m2) T_(m3) Heat of Fusion T_(c1) T_(c2)Sample (° C.) (° C.) (° C.) (J/g) % Cryst. (° C.) (° C.) IE1 120.8 108.8NA 135.2 46.3 108.8 98.2 IE2 119.3 107.6 NA 136.5 46.7 107.4 98.2 IE3123.1 120.2 109.3 142.4 48.8 108.0 NA LLDPE1 123.4 121.5 109.0 142.748.9 108.0 NA LLDPE2 119.4 107.9 NA 139.6 47.8 107.1 98.2 LLDPE3 117.0107.2 NA 140.0 47.9 105.1 NA

TABLE 9 Neutron Activation Data* Al Mg Ti V Hf Zr Cl Sample (ppm) (ppm)(ppm) (ppm) (ppb) (ppb) (ppm) IE1 46 570 1.1 1.56 ND@50 730 54 IE2 39510 0.5 1.3 ND@50 790 47 IE3 22.6 43 1.4 2.6 ND@50 1110 89 *Niobium (Nb)(5 ppm), tantalum (Ta) (50 ppb), chromium (Cr) (0.5 ppm), molybdenum(Mo) (50 ppb), and tungsten (W) (5 ppm) were not detected in any of theexamples at their respective detection limits, as indicated in theparentheses following each element. ND = not detected.

TABLE 10 1H NMR Data Total Unsatur- Vinylene/ Trisubstituted/ Vinyl/Vinylidene/ ation/ Sample 1000C 1000C 1000C 1000C 1000C IE1 0.09 0.0670.25  0.056 0.46 IE2 0.07 0.055 0.25  0.058 0.43 IE3 0.08 0.052 0.25 0.055 0.43 LLDPE1 0.06 0.036 0.24  0.046 0.39 LLDPE2 0.08 0.062 0.28 0.058 0.47 LLDPE3 0.08 0.085 0.097 0.027 0.29

Film Examples

In the below Examples, IE1, IE2, IE3, LLDPE1, LLDPE2, and LLDPE3 areused to make different films as specified further for each Example. Inaddition, a low density polyethylene (identified as “LDPE” below) isalso used. The LDPE is EB853/72 which is commercially available fromBraskem and has a density of 0.922 g/cm³ and a melt index (I₂) of 1.00g/10 min.

IE1, IE3, LLDPE1, and LLDPE3 each include 1000 ppm of a slip agent and2500 ppm of an antiblock. IE2 includes 900 ppm of a slip agent and 2500ppm of an antiblock. LLDPE2 includes 900 ppm of a slip agent and 5000ppm of an antiblock.

Example 1

Inventive Film 1 and Comparative Film A are fabricated on a 3 layerblown film line using a 200 mm die diameter at a speed of 190 kg/hourand a blow up ratio (BUR) of 2.5. Each of the 3 layers has the samecomposition as shown in Table 11. The films have a nominal thickness of50 microns. The Dart Impact (Method A), Elmendorf tear in the machinedirection, and puncture resistance of the films are measured and theresults are shown in Table 11.

TABLE 11 Dart Elmendorf Puncture Layer Impact Tear, MD ResistanceComposition (grams) (grams) (J/cm³) Comparative 85% LLDPE1 417 834  9.3Film A 15% LDPE Inventive 85% IE1 450 858 25.0 Film 1 15% LDPE

Inventive Film 1 using IE1 shows an improvement in dart impact andElmendorf Tear, and a significant improvement in puncture resistancerelative to Comparative Film A.

Example 2

Inventive Film 2 and Comparative Film B are fabricated on a 3 layerblown film line using a 450 mm die diameter at a speed of 420 kg/hourand a blow up ratio (BUR) of 2.5. Each of the 3 layers has the samecomposition as shown in Table 12. The films have a nominal thickness of70 microns. The Dart Impact (Method A) and Elmendorf tear in the machinedirection of the films are measured and the results are shown in Table12.

TABLE 12 Dart Elmendorf Layer Impact Tear, MD Composition (grams)(grams) Comparative 80% LLDPE2 127 309 Film B 20% LDPE Inventive 80% IE2361 432 Film 2 20% LDPE

Inventive Film 2 using IE2 shows a significant improvement in dartimpact and Elmendorf Tear relative to Comparative Film B.

Example 3

Inventive Film 3 and Comparative Film C are fabricated on a monolayerblown film line using a 250 mm die diameter at a speed of 150 kg/hourand a blow up ratio (BUR) of 2.5. The films have the compositions shownin Table 13 and each has a nominal thickness of 70 microns. The DartImpact (Method A), Elmendorf tear in the machine direction, and punctureresistance of the films are measured and the results are shown in Table13.

TABLE 13 Dart Elmendorf Puncture Layer Impact Tear, MD ResistanceComposition (grams) (grams) (J/cm³) Comparative 85% LLDPE1 386 1331 7.11Film C 15% LDPE Inventive 85% IE3 392 1281 9.60 Film 3 15% LDPE

Inventive Film 3 using IE3 shows comparable physical properties relativeto Comparative Film C.

Example 4

Inventive Film 4 and Comparative Films D and E are fabricated on amonolayer blown film line using a 250 mm die diameter at a speed of 150kg/hour and a blow up ratio (BUR) of 2.5. The films have thecompositions shown in Table 14 and each has a nominal thickness of 70microns. The Dart Impact (Method A), Elmendorf tear in the machinedirection, and puncture resistance of the films are measured and theresults are shown in Table 14.

TABLE 14 Dart Elmendorf Puncture Layer Impact Tear, MD ResistanceComposition (grams) (grams) (J/m³) Comparative 80% LLDPE1 258 558 12.27Film D 20% LDPE Comparative 80% LLDPE3 263 542 19.41 Film E 20% LDPEInventive 80% IE1 311 560 25.43 Film 4 20% LDPE

Inventive Film 4 using IE1 shows improvement in dart impact and punctureresistance, and comparable Elmendorf Tear, relative to Comparative FilmD and E.

We claim:
 1. A film comprising a layer comprising: (a) 50% or more byweight or more of a polyethylene composition comprising the reactionproduct of ethylene and optionally one or more alpha-olefin comonomers,wherein said polyethylene composition is characterized by the followingproperties: (i) a melt index, I₂, measured according to ASTM D 1238(2.16 kg, 190° C.), of from 0.5 to 10 g/10 min; (ii) a density measuredaccording to ASTM D792 of less than 0.935 g/cm³; (iii) a melt flowratio, I₁₀/I₂, wherein I₁₀ is measured according to ASTM D1238 (10 kg,190° C.) of from 6.0 to 7.5; (iv) a molecular weight distribution(M_(w)/M_(n)) of from 2.8 to 3.9; (v) a vinyl unsaturation of greaterthan 0.12 vinyls per one thousand carbon atoms; and (vi) a ratio ofz-average molecular weight (M_(z)) to weight average molecular weight(M_(w)) (M_(z)/M_(w)) of from 3.0 to 4.0; and (b) 50% or less by weightof a low density polyethylene.
 2. The film of claim 1, wherein the lowdensity polyethylene has a melt index, I₂, range of from 0.1 to 5 g/10min.
 3. The film of claim 1, wherein the film comprises from 5 to 30% byweight of the low density polyethylene.
 4. The film of claim 1, whereinthe film is a monolayer film.
 5. The film of claim 1, wherein the filmis a multilayer film.
 6. The film of claim 1, wherein the polyethylenecomposition is formed in the presence of a catalyst compositioncomprising a multi-metallic procatalyst via solution polymerization inat least one reactor.
 7. The film of claim 6, wherein the solutionpolymerization occurs in a single reactor.
 8. The film of claim 6,wherein the polyethylene composition has a metal catalyst residual ofgreater than or equal to 1 parts by combined weight of at least threemetal residues per one million parts of polyethylene polymer, whereinthe at least three metal residues are selected from the group consistingof titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium,molybdenum, tungsten, and combinations thereof, and wherein each of theat least three metal residues is present at greater than or equal to 0.2ppm.
 9. The film of claim 6, wherein the polyethylene composition has anAl:Ti ratio of from 6 to
 15. 10. An article made from the film accordingto claim
 1. 11. The article of claim 10, wherein the article is a pouch.12. A film comprising a layer comprising: (a) 50% or more by weight ormore of a polyethylene composition comprising the reaction product ofethylene and optionally one or more alpha-olefin comonomers, whereinsaid polyethylene composition is characterized by the followingproperties: (i) a melt index, I₂, measured according to ASTM D 1238(2.16 kg, 190° C.), of from 0.5 to 10 g/10 min; (ii) a density measuredaccording to ASTM D792 of less than 0.935 g/cm³; (iii) a melt flowratio, I₁₀/I₂, wherein I₁₀ is measured according to ASTM D1238 (10 kg,190° C.) of from 6.0 to 7.5; (iv) a molecular weight distribution(M_(w)/M_(n)) of from 2.8 to 3.9; and (v) a vinyl unsaturation ofgreater than 0.12 vinyls per one thousand carbon atoms; and (b) 50% orless by weight of a low density polyethylene, wherein the polyethylenecomposition is formed in the presence of a catalyst compositioncomprising a multi-metallic procatalyst via solution polymerization inat least one reactor, wherein the polyethylene composition has a metalcatalyst residual of greater than or equal to 1 parts by combined weightof at least three metal residues per one million parts of polyethylenepolymer, wherein the at least three metal residues are selected from thegroup consisting of titanium, zirconium, hafnium, vanadium, niobium,tantalum, chromium, molybdenum, tungsten, and combinations thereof, andwherein each of the at least three metal residues is present at greaterthan or equal to 0.2 ppm.
 13. A film comprising a layer comprising: (a)50% or more by weight or more of a polyethylene composition comprisingthe reaction product of ethylene and optionally one or more alpha-olefincomonomers, wherein said polyethylene composition is characterized bythe following properties: (i) a melt index, I₂, measured according toASTM D 1238 (2.16 kg, 190° C.), of from 0.5 to 10 g/10 min; (ii) adensity measured according to ASTM D792 of less than 0.935 g/cm³; (iii)a melt flow ratio, I₁₀/I₂, wherein I₁₀ is measured according to ASTMD1238 (10 kg, 190° C.) of from 6.0 to 7.5; (iv) a molecular weightdistribution (M_(w)/M_(n)) of from 2.8 to 3.9; (v) a vinyl unsaturationof greater than 0.12 vinyls per one thousand carbon atoms; and (vi)z-average molecular weight (M_(z)) of from 380,000 to 450,000 g/mol; and(b) 50% or less by weight of a low density polyethylene.